Pneumatic tool.



2 SHEETS--`SHEET I.

0 Efica Patenta& Nov. 20, 1917.

C. CHRISTIANSEN. PNEUMATIC TOOL.

` AFPLICATION FLED SEPT- 22. l9l5 A 1`,247,080.

' STATEs PATENT OFFICE..

speomoation of Letters Pafent.

Patented Nov. 20, 191 '7.

" oato med September sa, isis, semi a. 52,070;

To all 'whom it may concem:

` Be it known that I, HALas Cn'isrmxsm, .a citizenlof the German'Empire,` resdentat Gelsen kirchen, in the' Kingdom of Prussa, GermanzEmpi-e, have inventednew and useful Improvementsin Pneumatic Tools, of whchthe following is 'a specification.

In 4 known `pneuiiatic tools, particularly riveting hahmers, mms, and the like, conm'trollin' `'gear-shave been-used; in' which the contro ing "member is-'moved in one direci tion hy the air compressed by the piston n direction bythe fresh 'air p'ressure acting on a permanently loaded surface. Controllng the cylinder, and is movedin the reverse gears' of--this kind have the disadvantage, that the reversing is not eflectedsufliciently quick- 'and easy. If, `for instance,"the surface ongwlich .the fresh air pressure acts permanently, is made too large, the backpressure inreversingyby means of the air .compressed in the cy'li'der, will become too reat. If,-o`n the other hand, the said surace" is `m`ade too small,` the rversng by means of the fresh'air pressure is performed to"=slowly, and only after' a consider-able drop in premte in the cylinder has ocair compressed by the pisten in th'ecylindey cun-ed.

The object of the present invention is to obviate these disadva ntages. While the reversing of the contrllig'member in one direetio'n is eflected in known manner by. the

'the invention consists in' providing means smallersurface is opposed in n the accompanying; drawings, Figures '1- and 2` are' longit idinal' sections ;through cylin y such means, the fresh air pr'essure f actingp on a large surface is utiliedfor rebodying my invention with the controlling valve' and the piston in different positions.

Figs. 3 'and 4 are vertical sections through the eylinder and controlling valve on `an enlarged scale in a plane at an an le to the plane of Figs. 1 and 2, clearly il ustrating the course and arrangement of the passages.

Figs. 5 and 6 are 'vertical sections of 'a form of a eup-shaped slide.

'the central` axis' of a pneumatc tool em- I modification of the controlling valve in the In Figs. 1 to 4 of the drawings a desigi nates ,the'cylinder'and b the piston adapted to reciprocate therein,` said cylinder being closed by 'a head a' screwe'd onto the rear end thei-cof. The head has an internal an-,

nular rib a forming an annular air passage a, which isconnected to an *air supply pipe' (not shown) through a passage zu The passage a communicates withan ad- &

mission passage g, Fig. 3, which extendsi i longitdinall through the wall'of the `cylirder, and is a apted to communicate with the 5\ interior ofthe latternear its top, through a transverse passage h and annular channel h' and alt a point below the latter the passage g is adapted to communicate With the er through'a transverse passage i and an annular channel i'.

A control' valve c is reciprocally mounted in the cylinder'between the head ti' and n annular valve seat d formed in the interi wall of the eylinder. The 'lower ortion` of the valve wa l1 is reduced in thckness. to

form a small annular shoulder 'e',` on the outer periphery of the valve, and substantially midway between'the two ends of the valve,l the diameter is increased to form an anmlar shoulder f on its outer surface and annular shoulders f', f, on its inner surface.

'The 'shoulders f, f', and f, arelarger than the shouldere, so as to form larger pressure areas, the purpose of which will be herenafter explained the valve seat d and theannular channel i" there is formed an annular groove k', which is connected, by a transverse passage k, with In the inner 'wall of the cylinder between i a assage' Z* extendig u ward lon 'tudina ly through the wall of t e cylinden -The passage Z com municates with a tr hsverse passage m which terminates in a i nnular channel m' and above the latter there is an annuler channel n open to the atmosphere through an exhnst pnssage '0. Communicton between Channels m' and n s had through an annuhr groove c' in the valve' a 2 when the lttler is seatcd.

An annular stopped channel j is formed in' the cylindcr wnll between channels z" und tween said Channels is cut Ofl' by portion of'the vzrlve. above the shouldene when the valve is seatcd, as shown in Fig. 3.

The channel 'j is connected with the' exhaust passage o hy n passage q which is controlled by the enlarged portion of the valve between thegroovcs c', c said passage being closed when the valre is setcd as shown in Fi 8.

A l ng'tudinnl passage l' extends down- -ward from the transvere passage k and is connected with the cylinder at the lower end thcreof by u transverse passage r.

s 'indicates nn cxhaustpassage extendin '-lo ngitudinally through the cylinder an whichtopens into the interier of the latter near the vlve sent (Fig. 1) and opens near the upper end of the vnlve into an annular groove e' which is adupted to communicate wth 'the channel n through the groove c' when the valve is raised (Figi 4) and closed by the upper end portion of the valve when the latter is seated (Fig. 3).

` The cylinder is vented -to the ntmosphere through ports 77, p', which ure controlled hy the -pston.

The operation of the above described valve mechnnism is ns follows': With the parte in the position shown in Fgs. l and 3 with -the piston :t the rear endof its stroke end'thc valv'e c at the forward limit of its movement, live eiradmitted at 2 fiows throughpassuge (1 into passages (1 and It and channel h' over the top of volve c down tlfrough' itsinter''or to the rear of the pisten bend drives the htter forward.

Air passing through the vulve exerts pressure on the nter or a'nnuhr shoulders f', f so that the valve is not' premnturehv raised from its i I AS nsses the exhnnst ports p', the present-c n the valve and space of'tiiecylndcr. behind the piston is relievel. Live a-ir entcrs passage z', sinuieu-ousl r with lhc ndniseioi of nir to passage nl flrfws fro passage i into c|;ncl i'. through zroin'e e* into channel j and against the ex- :terio shoulder fr" Sinltuneouly with the transvers passage# whiclrtbrminates n diameter us said' tpper end of thevalv; i

rduction of pressure'insilethe valve the 66 t in channel j raisesthe valve from -i seat d and' closes passage The (live air iu channel i' now acts on the h'aller shoulder e `and maiutains the valve in its raised positon (Fig. 4). The channel j is now vented 70 to the atmospherc through passages q and o. As soon as the valvc s-'raised, the interors of'the vllve audcylind'e'r are vented through passage a, ehannols a' and n, and passage o. .76 The live air is now admitted from passae i; channel i' past the reduod portion of t e valve below the shouldcra into the channel Ic', passage k, passage l' and asstge r into the a 'wc y .of thegcylinder' he' ow the piston ao b an drives the latter back.

As soon as the pisten in its backwerd movement passes t e" iutke or lowere'ndt of the assage s, the aii-'in the cylider and valvc a ove the piston .is c'ompressed tos'uch' s'ia -nn extent that back 'presure of air on the shouldersf', f, overcomes the pressure of the -lve ar on small 'shoulder te, eonse quently, the valve ismoved downward from rthe position shown 'in Fig. 4 to the position p o' shown in Fig. 3 and the operation repeated. In other words, u on the downward 'stroke of the piston b, an' is'firt admitted to' the larger pressure surface f to' initiate' the movement of the valve, as this te uim m'ore force than is necessary to keep t e valve in motion when oncestarted to move. Port i is then 'cut off, and ait-'is admitted to then' smaller surface e'f'to complete the movement of the valve, `so that the valve strikes itoo seat with *a ver'y :small force; -thus savin wear on.both seat and valve. Upon' reverse of the piston'b'con'prssion of air therby cause; pres'sure on the nnbalanced internal surface f whiclfis opposed by pressuro' on the purallcl surface e, and thereafter the surface e is vented and 'pressure exe'rted on the larger surface f to cause the easy seating-of the valve.

In the modified fol-n shown in .Figs. 5 nd` i (i,` the controlling -val`re c isvin the` form of an inverted cup and is agially'm'ovabl'b etweer' an upper and lower annlar viilve seat df, d', respectively. -'An air adinssion' passageg' eomnnicates' with a s mply pipo. f' (not shown) as in'F-ig. 1. -'^-S`ail' 'as`sa-ge ex tends longitudinally through the wall of th n cyInde'r a and-is :idapted'` to communicat with the interier of'the cylinrlefthrough az' 1 4 'a The chamber t' -has :m xial openingj' at-- the top adapted to' comintnicato-iwithjza shoul er f ofthe valve.

,through the stelp'ped annular channel i' surrounding the va ve seat d'the channel i' communicatng e with a transverse passa e i* which commu-r nicates with the longit'u, inal passage gf.

The valve has a steme on its upper" end forming an annular shoulder f, said stem having 'a head e' adapted to close the' open-` u v tends longitudinally through t e wall of the cylinder and opens into the `latteat the` lower end thereof, the same as passage l' in Fis. 1 and?. a

passage o' which communicates with the atmos here extends transverselfi' through the cylin er and isconnecte'd wit the ste'pped annular channel i* b means of a passage q' which is controlled y the valve. This exhaust passage municate with the longitudina passage Z through" a transverse passage .m' -which is ada ted to communicate .with said passage 0' rough an annular ove c formed in the outer periphery of t e valve. f

s' indicates an exhaust passage extending longitudinall through the cylinder and opening into the letter below the lower valve seat d and communicating with an annular channel n' which is adapted to communicate through the annular groove 0 with an an- 'nular channel 'n in direct communication with the exhaust passage o'.

The operation of the modified formis as follows: With the valve in the position shown in Fig. 5 with the piston at the rear end of its stroke, live air admitted through f' flows through passage h? beneath 'the er edge of the valve 0 This air acts' on the piston b to drive it forward and simultaneously acts on the-inner closed end c' of the valve and` holds it in open position. Air from passage g' will also flow through passa ej', channel i, opening j' onto the As the area of the shoulder f is less than the area of the end c* of the valve, the air acting on the shoulder cannot move the valve until the pressure within the valve and cylinder is reduced by the piston opening the ports p, p'. As soon ae this reduction of pressure takes place, the air actng on the shoulder f moves the valve down or forward closing the opening j', opening the port of passage 10 and closin communication with the exhaust passage o by closing passage m'. The air now flows passage k' and passa el' into the interier of the cylinder below t e piston and` drives the letter back.

- The downward or forward movement of the valve closesthe opening j' and vents the k'. opens into the p nular channel n' and 'as the upper end of t e piston paseee the 0-' is also' arran edfto com-- chamber i to the atmosphe'e throu h assages q' and, o'. Pressureon the' ea e' is suflicient to hold the 'valve on its seat d' durng a portion of'the return or back stroke a "of `the piston'. The space af: of thecylinder is vented to'the atmosphere after the pistoh passes the ports p', p through the pa a'; which, at the forward or downward movement of the piston, is'vented to the atmosphere through the annular groove o',-.n-

assage o'. As soon lower end of passage s' and closes the same,

compremion takes place in' the cylinder above the piston and inside the valve and exerts a pressure on the large surface of the end o' suflicient to overcome 'the pressure of live air on the`small top surface e' of the head e', thus raising the valve fromthe 'position shown in Fig. 6 to the position shown in Fig. 5, and permits thelve air to flow beneath the lower end of the valve.

The transference of pressure froni the larger surface'f' to the smaller surface e' upon closin the valve, and vice versa u n opening is or the same purpose as descri d with reference' to Figs. 1-4.

I claim bringing into operation, after the said relief of pressure, a smaller pressure surface to complete the movement of said valve in said direction. r I *2. A neumatictool, comprising a cylinder, a piston therein and a cylindrcal openended distributing valve having a plurality of pressure surfaces thereon, air passages communicating with said surfaces, one of said surfaces 'being a large surface to initiatethe movement of said valve in %i direction, means to disconnect said surf from its air supply and vent the surface to the atmosphere, and another smaller surface maintained underair pressure during the remainder of the movement of saidvalve to complete the movement of the said valve in the same direction.

3. In a pneumatic tool, a cylinder, a piston therein, and a cylindrical open-ended valve at one end of said cylinder, said valve having an internal press'ure surface and two external annular pressure surfaces of different areas, means including porte and assages coperating with sai valve an its neumatic tool comprising a cyliny der, a pston therein and a cylindrical open' pressure surfacesto initiate themovement of the valve in one direction by action on the larger external surface and before completing the valve movement to vent the pressure on the smaller Valve surface, and upon e reversal of sad valv to releve the pressure from said smaller external surface and exert pressure on the larger of sad surfaces.

In witness whereof I have hereuhto set my hand inpresence' qftw'o witnesses.

CHARLES CHEISTIANSEN.

witnesses: J. D. ZmsEKE,

EL; KAEMPERS. 

